Apparatus for changing and indicating the rotary and axial position of a printing member

ABSTRACT

Apparatus for dynamically positioning the angular and axial position of a printing roller and means for indicating these positions comprising a printing roller driven by a gear through a motor-driven harmonic gear drive for changing the angular phase relationship of the driving gear and the printing roller; a manually operable worm gear drive for axially shifting the printing roller relative to a reference point; a read-out dial attached to a secondary output of the harmanic gear motor drive for indicating the angular position of the printing roller relative to the roller driving gear; and a linear dial for indicating the axial position of the printing roller.

United States Patent Warren A. Stewart Monkton, Md.

Aug. 29, 1968 Feb. 23, 1971 Koppers Company, Inc.

Inventor App]. No. Filed Patented Assignee APPARATUS FOR CHANGING AND INDICATING THE ROTARY AND AXIAL POSITION OF A PRINTING MEMBER 7 Claims, 6 Drawing Figs.

US. Cl.

Int. Cl.

B411 13/14 Field of Search Jacobson" Jacobson Primary Examiner-Robert E. Pulfrey Assistant Examiner-.1. Reed Fisher Attorneys-Oscar B. Brumback, Boyce C. Dent and Olin E.

Williams ABSTRACT: Apparatus for dynamically positioning the angular and axial position of a printing roller and means for indicating these positions comprising a printing roller driven by a gear through a motor-driven harmonic gear drive for changing the angular phase relationship of the driving gear and the printing roller; a manually operable worm gear drive for axially shifting the printing roller relative to a reference point; a read-out dial attached to a secondary output of the harmonic gear motor drive for indicating the angular position of the printing roller relative to the roller driving gear; and a linear dial for indicating the axial position of the printing roller.

PATENTEDFEB23|971 sum 1 or 2 INVENTOR. WARREN A. 5TWART BY rfi'z'ameg PATENTEU FEB23 1911 SHEET 2 OF 2 INVENTOR. WARREN A. 5 TE WAFT ofllmwz APPARATUS FOR CHANGING AND INDICATING THE ROTARY AND AXIAL POSITION OF A PRINTING MEMBER BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates generally to machine elements and mechanisms and more particularly to adjustable gearing.

2. Description of the Prior Art In the printing of corrugated paperboard blanks, rubber dies are secured to one or more printing rollers which must be kept in register with each other and in register with the blank feeding mechanism to assure registration of the printed indicia on the blank. Since the dies may be improperly positioned around the circumference of and along the axis of the printing rollers, means must be provided for adjusting the angular or circumferential position of the rollers with respect to each other and with respect to the driving gear train. Equally important is means for adjusting the axial position of the printing rollers to provide lateral positioning of the dies across the width of the blank.

Various gearing arrangements have proven capable of performing the required phase change function although generally speaking they are usually complex and expensive, One example is illustrated in I-I.B. Greenwood U.S. Pat No. 2,677,971, which arrangement is limited in that it is manually operated and relative movement between the printing roller and its driving gear is limited to a few degrees. Preferably, the

printing roller is rotatable relative to the driving gear throughout a full 360 and is not limited to a single rotation. Thus, if the mechanism is motor-driven, the roller may be easily rotated to aid in securing the printing dies on the roller. A complex arrangement providing for 360 of rotation is illustrated in H.D. Ward, Jr. U.S. Pat. No. 2,986,952. Other arrangements are shown in U.S. Pat. Nos. 1,868,385; 2,030,027; 2,030,028 and 2,098,112.

It has been suggested that, as outlined in an article appearing in the April 28, 1965 issue of Design News, a Cahners publication located at 3375 S. Bannock St., Englewood, Colorado 801 10, strain wave gearing such as that illustrated in C.W. Musser U.S. Pat No. 2,906,143 to be adapted to adjusting the phase relationship between printing rollers and between the rollers and their driving gears. A similar reference may be found in a brochure published by the Harmonic Drive Division of United Shoe Machinery Corporation, Balch St., Beverly, Mass. 01915, Form No. 5033. Nevertheless, no one seems to have satisfactory applied strain wave gearing (commonly referred to as harmonic drives) to the registration of printing rollers in corrugated paperboard blank finishing equipment, probably due to the problems involved. To be satisfactory, such gearing must provide for registration of the printing rollers with a feeding means for the blanks and for registration with each other for longitudinal registration of printing on the blanks, Read-out means must be provided for indicating register or nonregister positions of the rollers and, preferably, readable during rotation of the rollers. End-adjustment means must be provided for axially shifting the printing rollers transversely along with respect to the path of travel of the blanks to register printing transversely along the width of the blanks. Read-out means for indicating transverse registration is necessary.

SUMMARY OF THE INVENTION The present invention overcomes the complexities of the prior art devices and successfully utilizes harmonic drive principles in combination with means for angular position readout and end-adjustment with axial read-out means to provide dynamic angular phase adjustment of a full three hundred and sixty degrees while the printing machine is running; position read-out, both as to phase relationship and axial location, are readable while the machine is running.

The foregoing functions are accomplished by providing a harmonic drive of which is its rigid circular spline is coupled to the printing roller driving gear; its flex spline is coupled to the printing roller; and its wave generator is driven by a shaftmounted gear motor at such time as a change in phase is required between the driving gear and the printing roller. When no change in phase angle is occurring, the printing roller is driven by the driving gear indirectly through the rigid spline and the flexspline, the wave generator being held stationary by a brake incorporated in the gear motor.

Dynamic read-out is provided by a worm and worm wheel coupled to a secondary output of the gear motor, the secondary output rotating at the same speed as the primary output driving the wave generator. By providing the same reduction between the worm and worm wheel as used between the rigid spline and the flexspline, a graduated dial and pointer associated with the worm wheel indicates a the actual change in angular position between the drive gear and printing roller.

To accomplish end adjustment, a pair of worm gears are mounted in a stationary housing with one of the gears including internal screw threads meshing with corresponding external threads on the motor support which moves axially with the input shaft. The input shaft is bearing mounted to the printing roller indirectly through the harmonic drive and printing roller drive gear. The printing roller is axially slidable in bearings housed in the machine frame. Thus, as the threaded worm gear is rotated by the other worm gear, the wave-generator input shaft moves axially thereby moving the printing roller axially. A pointer attached to and moving with the motor support registers axial position of the printing roller along a scale provided on the stationary housing for the worm gears.

BRIEF. DESCRIPTION OF THE DRAWINGS The above and further objects and novel features of the invention will appear more fully from the following detailed description when the same is read in connection with the accompanying drawings. It is to be expressly understood, however, that the drawings are not intended as a definition of the invention but are for the purpose illustration only.

In the drawings wherein the like parts are marked alike:

FIG. 1 is a side elevation in cross section illustrating the invention coupled to a printing roller which is shown in plan view;

FIG. 2 is a plan view in partial cross section taken along the line 11-11 of FIG. 1 and illustrating the invention coupled to a printing roller located adjacent the printing roller of FIG. 1;

FIG. 3 is a sectional view of the harmonic drive taken along the line IIIIII of FIG. 1;

FIG. 4 is a plan view of the dynamic read-out indicator taken along the line IV-IV of FIG. 1;

FIG. 5 is a sectional view of the end adjustment taken along the line VV of FIG. 1; and

FIG. 6 diagrammatically illustrates two adjacent printing rollers each utilizing the present invention.

DESCRIPTION OF THE PREFERRED CONSTRUCTION The problem of registration is illustrated by the printing of a solid letter K on top of an outline of letter K in the center of blank 18 as shown at 20 in FIG. 1 using a conventional pair of adjacent printing rollers 10 and 12 which are axially slidably supported in bearings 14 housed in spaced apart machine frames 16a and 16b. These rollers l0, 12 of FIGS. 1 and 2 are illustrated in plan view with portions broken away to show the advance of a paperboard blank 18 beneath roller 10 (shown in solid lines) to a position beneath roller 12 (shown in dotted lines) as indicated by the large arrow in FIG. 1.

The outline 22 is first printed on blank 18 with die 24 (see FIG. 3) on roller 10; and the blank 18 is then advanced beneath roller 12 where solid letter K 26 is printed on the blank by die 25. It should be understood hat the blank advances continuously at a uniform velocity rather than intermittently.

If the dies on the rollers and 12 are not properly located, the outline letter K 22 may not be printed in the desired location as shown exaggerated by the dotted lines in FIG. 2. Similarly, the solid letter K 26 may be displaced as shown by the dotted lines in FIG. 1. The circumferential out of register condition can also be caused by an out of time relationship with the blank-feeding mechanism (not shown). It will be understood by those skilled in the art that one of the roller driving gears 28 mounted on journals 30 of rollers 10 and 12 will be coupled to the feeding mechanism by a gear train. The feeding mechanism, being a timed machine, will feed blanks l8 sequentially beneath the printing rollers 10 and 12. Thus, the indicia K will always be imprinted at the same relative location on successive blanks. Since the printing rollers may be uncoupled, to allow access to the dies, from the feeding mechanism gear train and from each other, and be rotated during such uncoupling, then it can be seen than an out of time condition can occur upon coupling of the rollers to the feeding mechanism and to each other.

To compensate (hence, the word compensator is commonly used to denote the phase adjusting mechanism) for the out of register condition, a phase adjusting mechanism and end adjusting mechanism is provided on one end of each of the printing rollers. The compensator is capable of changing the angular (or phase) position of the printing roller with respect to its driving gear. Accordingly, in operation, the compensator is actuated to rotate roller 10 until K 22 is imprinted in the desired circumferential position on blank 18 as shown in FIG. 2. This establishes registration with the feeding mechanism. Thereafter, the compensator associated with roller 12 is actuated until K 26 is in the circumferential position indicated by numeral in FIG. 1.

An end-adjustment is provided to laterally shift each printing roller along its axis until K indicia is located at the proper location across the width of the blank. Ordinarily, the amount of endadjustment required is small being of the order of onehalf inch in either direction from a center position between the machine frames 16a and 16b.

In accordance with this invention, dynamic angular phase adjustment is provided for the full 360 while the machine is operating as well as end-adjustment. Accordingly, driving member 28 for the printing member 10 is rotatable relative to said printing member and there is provided a phase shifting apparatus having an input 50 coupled to the driving member 28 and an output 40 coupled to printing member 10 with a wave generator 84 between input 50 and output 40 for changing the angular phase of output 40 with-respect to input 50. The power means 42 is coupled at 44 to wave generator 84 for selectively rotating the wave generator during rotation of driving member 28 in either a clockwise or counterclockwise direction to change the angular phase in a desired direction. Phase shift indicator 46 coupled by shaft 48 to power means 42 and driven thereby in the direction and at a distance corresponding to the output of said phase shifting apparatus indicates at dial 50 the angular relation of the printing member 10 relative to driving member 28. Also coupled by way of shaft 100 to said power means 42 is the axial end-adjustment means 160, 162 for axially shifting the power means 42 during rotation of driving member 28 to shift the printing member 10 axially and an axial indicator 192, 194 for indicating the axial position of the printing member.

As previously mentioned, a driving gear 28 is rotatably mounted on each of journals 30 of rollers 10 and 12 by conventional radial-thrust bearings 38. As is conventional practice, the driving gear 28 associated with roller 10 is driven by a gear train (not shown) connected to a blank-feeding mechanism. The driving gear 28 that is associated with roller 12 is driven by the driving gear that is associated with the roller 10 through an idler gear 39. Idler gear 39 is rotatably mounted, by roller bearing 43, to an idler stud 45 secured in a hole 47 in machine frame 16a by a washer 49 and screw 51 in an ordinary manner.

Each phase shifting mechanism (both are identical) includes three major portions: a harmonic drive 40 coaxially aligned with and secured to driving gear 28; a gear-motor 42 having a primary output shaft 44 in axial alignment with and coupled to harmonic drive 40 for changing the output of the harmonic drive; and a dial indicator 46 coaxially aligned with and coupled to a secondary output shaft 48 of gear motor 42 for indicating the relative angular position of the driving gear 28 with respect to its associated printing roller. Secondary output 48 is an extension of primary output 44 which extends through a hollow output shaft in gear-motor 42, to be subsequently explained.

The harmonic drive 40 includes a flanged rigid circular spline 50 mounted to the side of driving gear 28 by screws 52 in the ordinary manner. A flexible circular spline 54 is nested within rigid spline 50. One end of flexible spline 54 is closed by a radially-extending end portion 56 having a central opening surrounding a reduced shoulder portion 58 of journal 30. End portion 56 is secured for rotation with journal 30 by washers 60 disposed on either side of the end portion with screws 62 passing through both washers 60 and end portion 56 and into journal 30 in the ordinary manner. This construction also axially secures radial-thrust bearing 38 on reduced shoulder portion 64 of journal 30.

The open end of flexible spline 54 includes external spline teeth 66 around its outer periphery. These teeth are adapted to mesh with corresponding internal teeth 68 formed around the inner periphery of rigid spline 50.

Rigid spline 50 includes a radially-extending end portion 70 secured to it by screws 72 in the ordinary manner. Primary output shaft 44 is mounted for rotation within a central opening 74 in end portion 70 by a conventional radial-thrust bearing 76. Bearing 76 is retained on a reduced shoulder portion 78 of shaft 44 by a spacer 80.

Shaft 44 includes a further reduced shoulder portion 82 upon which a wave-generator cam 84 is secured for rotation therewith by a conventional shaft key 86, washer 88, and screw 90 in the ordinary manner. Wave-generator cam 84 is thus axially urged against spacer to retain bearing 76 on shoulder 78.

An elliptical roller bearing 92 is secured, as for example by a press fit, around the periphery of cam 84 which is also elliptical as illustrated in FIG. 3. The major diameter of the bearing 92, that is, the portion opposite the lobes of cam 84, urge the external spline teeth 68 into meshing engagement with the internal spline teeth 69.

Operation of the harmonic drive 40 is fully described in the aforementioned United Shoe Machinery brochure. Briefly, its operation is as follows. Driving gear 28 is secured to the rigid spline 50, as previously described, andis adapted for rotation around journal 30 by means of bearing 38. Journal 30 is secured for rotation with flexible spline 54. The wave-generator, comprising cam 84 and bearing 92, is held stationary by the primary output shaft 44 of braked gear-motor 42. The gear-motor rotates the wave-generator to change the angular or phase relationship between gear 28 and roller 12.

It should be understood that the flexible spline 54 is made of thin flexible metal (plastic materials can be used where transmitted torque is small) so that the wave-generator can deflect the external teeth 68 intoengagement with external teeth 66 at the two points opposite the lobes of cam 84. Thus, rotation of the wave-generator will result in a continuously moving waveform transferred to flexible spline 54. This causes the flexible spline 54 to rotate with a greatly reduced tangential motion. A full rotation of the wave-generator will produce a rotation of flexible spline 54 through a distance equal to the difference between the circumference of the rigid spline 50 and the circumference of flexible spline 54. Consequently, the actual reduction ratio can be obtained by dividing the difference between the two circumferences into the circumference of the flexible spline 54. Since the spline teeth on both the flexible spline S4 and rigid spline 50 have the same circular pitch, the actual number of teeth on each can be used as the circumferential measurement; the reduction ratio of any unit can be computed by dividing the difference between the number of teeth on the two splines into the number of teeth on the output member (flexible spline 54). For example, if the rigid spline 50 has 202 teeth and the flexible spline 54 has 200 teeth, the ratio would be Thus, when the harmonic drive is used in the ordinary manner with the rigid spline 50 fixed and the input going into wavegenerator 84, the output of flexible spline 54 would be one revolution for each hundred revolutions input.

However, as used in the present invention, the wave-generator 84 is held stationary (except when the angular phase is changed) and rigid spline 50 becomes the input with the flexible spline 54 remaining as the output. Thus, the output of flexible spline 54 is at the ration of 202:200 or 101:100. Consequently, the output of flexible spline 54 is 101 revolutions for each 100 revolutions of input to rigid spline 50.

Since the printing rollers and 12 must rotate at the same circumferential velocity as the lineal velocity of the blank being printed, it is necessary to establish the foregoing ration in reverse between the gear driving the blank feeding mechanism (not shown) and roller driving gears 28. For example, if the driving gear for the feeding mechanism has 100 teeth, then roller driving gear 28 must have 101 teeth to reduce its velocity by the same amount that the velocity of flexible spline 54 is increased by rigid spline 50. In this manner, the circumferential velocity of the printing rollers 10 and 12 is made equal to the lineal velocity of the blank 18 being printed.

A harmonic drive with a I002! ratio provides a high-resolution phase adjustment. One revolution of the wave-generator produces an adjustment of 3.6 on printing roller 10 or 12. If the roller is 50 inches in circumference, rotation of wavegenerator 84 one revolution by gear-motor 42 produces a circumferential shift of 0.5 inches of the roller relative to the driving gear 28. The wave-generator may be easily rotated a fraction of a revolution thereby producing a phase shift of a few thousandths of an inch so that very accurate registration is obtained.

Gear-motor 42 is a conventional shaft-mounted type including an integral brake for quickly stopping its output upon release of an energizing switch. Motor 42 is supported by motor support 100 attached to the motor by screws 102 passing through flange 104 and into the motor housing. Support 100 includes a shoulder portion 106 axially slidable in an opening 108 provided in a support housing 110. Housing 110 is secured to a machine subframe 112 by screws 114 passing through a flange 116 provided on housing 110. Motor support 100 is secured against rotation in housing 110 by a key 118 slidable in a keyway 120 provided in the housing.

Gear-motor 42 includes a hollow output shaft 122 which projects slightly beyond both sides of the motor gear casing as shown in FIG. 1. Primary output shaft 44 passes through hollow shaft 122 and is keyed thereto (not shown). Shaft 44 extends through an opening 124 provided in motor support 100 and is connected to the wave-generator as previously described. A conventional drum switch 126 is secured to housing 110 and is provided with an operating lever 128 which causes motor 42 to operate in a clockwise or counterclockwise direction depending on which direction lever 128 is pushed. Switch 126 is wired to motor 42 in an ordinary manner as well understood by those skilled in the art.

The present invention provides a read-out indicator that rotates only during an actual phase adjustment and, even then, it rotates slowly enough to permit visual inspection of the phase adjustment. This feature is advantageous in that the operator, having previously inspected a printed blank and measured the amount of nonregistration, can energize the compensator and simultaneously observe the amount of adjustment occurring. Thus, precise registration is obtainable with a single adjustment rather than by trial and error.

The read-out indicator 46includes a worm 130 secured to secondary output shaft 48 and driving a worm wheel 132. Shaft 48 is merely an extension of primary output shaft 44 extending through the hollow output shaft 122 of motor 42. Worm 130 is secured to shaft 48 in any convenient manner such as setscrews (not shown). Shaft 48 also has screw threads 134 upon which a threaded collar 136 is tightened to draw reduced shoulder portion 138 tightly against hollow shaft 122 to secure the output shaft 44 and motor 42 together.

Worm wheel 132 is secured on a stud 140 which is rotatably mounted in an opening 142 in a worm housing 144. Housing 144 is secured to the casing of motor 42 by screws 146 passing through a flange 148 provided on housing 144. A dial 150 is secured for rotation with stud 140 adjacent worm wheel 132. A transparent face plate 152 is secured to housing 144 above dial 150.

The reduction ratio of worm 130 and worm wheel 132 is made identical to the reduction ratio of the harmonic drive. Accordingly, if the wave-generator (cam 84) is rotated one full revolution by shaft 44, to cause a phase shift of 3.6 of the printing roller, then worm 130 will be rotated one full revolution by shaft 48 and worm-wheel 132 will rotate 3.6. Thus, dial 150 may have lined graduations 154 that correspond to the inches of circumference of the printing roller. Fractional lines may be placed between the inch line graduations if desired. Transparent face plate 152 includes a 0 or starting line 156 from which phase shifting of the printing roller may begin. The lines 154 and zero line 156 are illustrated in FIG. 4. Thus, it can be seen that dial 150 rotates only when a phase adjustment is made. The dial will turn relatively slowly because of the geared down speed of the gear-motor output 122, for example one revolution per minute, so that the amount of phase shift can be readily observed by the operator.

End-adjustment is provided by first providing a conventional worm gear 160 between a pair of thrust bearings 162 mounted in housing 110 by a sleeve 164. Sleeve 164 is secured to housing 110 by screws 166 passing through a flange 168 provided on the sleeve and into the housing. The central opening of worm gear 160 is provided with screw threads 170 which mate with corresponding threads 172 formed on the periphery of motor support 100. Thus, as worm gear 160 is rotated, it will cause motor support 100 to move axially in a direction corresponding to the direction that gear 160 is rotated. Motor which is, 100 is, as previously explained,

secured to motor 42 which is in turn, secured to shaft 44. Shaft 44 is rotatably connected to rigid spline 50 via thrust bearing 76 and end plate 70. Spline 50 is connected to driving gear 28 which is rotatably mounted on journal 30 by thrust bearing 38. Thus, axial shifting of motor support 100 causes the printing roller to be axially shifted.

Worm gear 160 is rotated by rotation of a similar smaller diameter worm gear which is, of course, positioned for meshing engagement with gear 160. Gear 180, as best illustrated in FIG. 5, is secured for rotation in the conventional manner to a shaft 182'. Shaft 182 is supported in a holder 184 which is itself secured to housing 110 by screws 186 passing through a flange 188 provided on the holder and into the housing. A handwheel 190 is secured for rotation with shaft 182 to enable the operator to easily turn the shaft to effect end-adjustment. If desired, a conventional shaft clamp (not shown) may be provided to prevent rotation of shaft 182 by normal machine vibrations when end-adjustment is not being made.

A pointer 192 is fastened to motor support 100 (See FIG. 1). A graduated scale 194 is fastened to fixed housing 110 adjacent pointer 192. As support 100 is shifted axially, the pointer 192 will indicate the end-adjustment distance traveled along scale 194.

FIG. 6 in addition to illustrating the printing rollers, also schematically illustrates the conventional impression cylinders 200 used to press the blanks 18 against dies 24 ad and 28. Also shown are conventional support rollers 202 for supporting the blanks as they advance from one printing roller to the next.

In operation, dies 24 and 28 are secured in the known manner to printing rollers and 12, respectively. ink is applied to the dies by conventional inking apparatus. Thereafter, one or more blanks are advanced by the feeding mechanism (not shown) between the pairs of printing rollers and impression cylinders. The blank is examined for register by the operator. If axial end-adjustment is required, the operator measures the amount and then turns handwheel 190 until pointer 192 has moved along scale 194 the correct distance. If circumferential adjustment is required, again the distance is measured and then the gear motor is energized to rotate in the proper direction by drum switch lee lever 128 until dial 150 has rotated the correct distance past the zero line 156.

The foregoing procedure can be used to register the outline of K 22 (roller 10) with respect to the feeding mechanism, that is, position it the correct distance from the forward and side edge of the blank. Thereafter, the same adjustments can be made to roller 12 to register solid letter K 26 with outline letter K 22 to form the complete indicia K 20. The machine can be started again and the registration will be accurate. If for some reason it is not, the operator can make final adjustments while the machine is running as set forth above.

lclaim:

1. Apparatus for changing and indicating the angular phase and axial position of a printing member comprising;

a driving member for said printing member rotatable relative to said printing member;

phase shifting apparatus having an input coupled to said driving member and rotatably driven thereby and having an output coupled to said printing member and further having a wave-generator between said input and said output for changing the angular phase of said output with respect to said input;

said phase shifting apparatus including:

a. a rigid circular spline secured for rotation with said driving member and having internal spline teeth thereon;

b. a flexible circular spline of smaller diameter than said rigid spline supported within said rigid spline and having external spline teeth thereon;

c. an elliptical wave generator supported within said flexible spline and adapted to deflect said flexible spline to a correspondingly elliptical shape for urging said external teeth into meshing engagement with said internal teeth substantially opposite the foci of said elliptical wave generator;

power means having a primary output coaxially coupled to said printing member through said wave-generator and said flexible spline for selectively rotating said wavegenerator in either a clockwise or counterclockwise direction during rotation or nonrotation of said driving member thereby changing the radially angular position of meshing engagement between said internal and external teeth;

said power means including a secondary output axially opposite to said primary output;

phase indicator means coupled to said secondary output and rotated thereby in a direction and at a distance corresponding to the direction and distance of rotation of said primary output for indicating the angular relation of said printing member with respect to said driving member;

said power means including an output shaft coupled to said printing member through said elliptical wave-generator and said flexible spline;

axial end-adjustment means coupled to said power means for axially shifting said output shaft during rotation or nonrotation of said driving member to thereby axially shift said printing member; and

axial indicator means associated with said power means for indicating the axial position of said printing member.

2. The apparatus of claim 1 wherein said driving member is a spur gear to rotatably mounted on one end of said printing member.

3. The apparatus of claim 2 wherein said power means is a gear-motor mounted coaxially with said phase shifting apparatus.

4. The apparatus of claim 3 wherein said phase shift indicator means includes a worm coupled with a secondary output of said gear-motor for driving a worm wheel associated therewith and printing member graduated dial coupled to said worm wheel for indicating the direction and distance of the phase shift of said printing member with respect to said driving member.

5. The apparatus of claim 4 wherein said end-adjustment means includes:

first and second worm gears fixed in rotatable operative engagemcnt in a stationary housing;

a movable support secured to said gear-motor and adapted for sliding engagement within said housing along the axis of said printing member;

said gear-motor including an output shaft coupled to said printing member through said elliptical wave-generator and said flexible spline;

said first worm gear having internal screw threads in operative engagement with corresponding external threads on said movable support; and

a handwheel coupled to said second worm gear for rotating said first worm gear through said second gear whereby said first worm gear axially shifts said movable support to thereby shift said printing member through said output shaft coupled to said printing member.

6. The apparatus of claim 5 wherein said axial indicator means includes a pointer secured to said movable support and a graduated scale secured to said stationary housing adjacent said pointer whereby axial movement of said support moves said pointer along scale for indicating the axial shift of said printing member.

7. Apparatus for changing the angular phase of first and second printing rollers with respect to driving means therefor and with respect to each other and for changing the axial position of said rollers comprising, in combination:

a first spur gear mounted on one end of said first printing roller rotatable relative thereby by said driving means;

a second spur gear mounted on one end of said second printing roller rotatable relative thereby by said first spur gear;

substantially identical phase shifting apparatus coaxially coupled to each of said spur gears, each shifting apparatus having an input rotatably driven by its associated spur gear and an output coupled to its respective printing roller, each shifting apparatus having a coaxial wavegenerator radially aligned between said input and said output for changing the angular phase of said output with respect to said input whereby the angular phase of said first printing roller is changed with respect to said driving means upon rotation of its associated wave-generator and the angular phase of said second printing roller is changed with respect to said first printing roller upon rotation of its associated wave-generator; each of said phase shifting apparatus including: a. a rigid circular spline secured for rotation with said driving member and having internal spline teeth thereon;

b. a flexible circular spline of smaller diameter than said rigid spline supported within said rigid spline and having external spline teeth thereon;

. an elliptical wave-generator supported within said flexible spline and adapted to deflect said flexible spline to a corresponding elliptical shape for urging said external teeth into meshing engagement with said internal teeth substantially opposite the foci of said elliptical wavegenerator;

a gear-motor for each of said phase shifting apparatus having a primary output coaxially coupled to its respective printing member through said wave-generator and said flexible spline for selectively rotating said wave-generator in either a clockwise or counterclockwise direction during rotation or nonrotation of said driving member thereby changing the radially angular position of meshing engagement between said internal and external teeth;

axial end-adjustment means for each of said printing rollers including:

first and second worm gears fixed in rotatable operative engagement in a stationary housing;

a movable support secured to said gear-motor and adapted for sliding engagement within said housing along the axis of said printing member;

said gear-motor including an output shaft coupled to said printing member through said elliptical wave-generator and said flexible spline;

said first worm gear having internal screw threads in operative engagement with corresponding external threads on said movable support;

each of said second worm gears having a handwheel coupled thereto for rotating said worm gears whereby said first worm gear axially shifts its associated movable support to thereby shift its associated printing roller;

indicator means coaxially coupled to each of said gear-motors including a third worm coupled with a secondary output of said gear-motor for driving a fourth worm wheel in operative rotatable engagement therewith and a graduated dial coupled to said fourth worm wheel for indicating the direction and distance of the phase shift of the associated printing roller; and

axial indicator ma means associated with each of said gearmotors including a pointer'secured to said movable support and a graduated scale secured to said stationary housing adjacent said pointer whereby axial movement of said support by said handwheel moves said pointer along said scale for indicating the axial shift of each of said printing rollers, 

1. Apparatus for changing and indicating the angular phase and axial position of a printing member comprising; a driving member for said printing member rotatable relative to said printing member; phase shifting apparatus having an input coupled to said driving member and rotatably driven thereby and having an output coupled to said printing member and further having a wavegenerator between said input and said output for changing the angular phase of said output with respect to said input; said phase shifting apparatus including: a. a rigid circular spline secured for rotation with said driving member and having internal spline teeth thereon; b. a flexible circular spline of smaller diameter than said rigid spline supported within said rigid spline and having external spline teeth thereon; c. an elliptical wave generator supported within said flexible spline and adapted to deflect said flexible spline to a correspondingly elliptical shape for urging said external teeth into meshing engagement with said internal teeth substantially opposite the foci of said elliptical wave generator; power means having a primary output coaxially coupled to said printing member through said wave-generator and said flexible spline for selectively rotating said wave-generator in either a clockwise or counterclockwise direction during rotation or nonrotation of said driving member thereby changing the radially angular position of meshing engagement between said internal and external teeth; said power means including a secondary output axially opposite to said primary output; phase indicator means coupled to said secondary output and rotated thereby in a direction and at a distance corresponding to the direction and distance of rotation of said primary output for indicating the angular relation of said printing member with respect to said driving member; said power means including an output shaft coupled to said printing member through said elliptical wave-generator and said flexible spline; axial end-adjustment means coupled to said power means for axially shifting said output shaft during rotation or nonrotation of said driving member to thereby axially shift said printing member; and axial indicator means associated with said power means for indicating the axial position of said printing member.
 2. The apparatus of claim 1 wherein said driving member is a spur gear to rotatably mounted on one end of said printing member.
 3. The apparatus of claim 2 wherein said power means is a gear-motor mounted coaxially with said phase shifting apparatus.
 4. The apparatus of claim 3 wherein said phase shift indicator means includes a worm coupled with a secondary output of said gear-motor for driving a worm wheel associated therewith and printing member graduated dial coupled to said worm wheel for indicating the direction and distance of the phase shift of said printing member with respect to said driving member.
 5. The apparatus of claim 4 wherein said end-adjustment means includes: first and second worm gears fixed in rotatable operative engagement in a stationary housing; a movable support secured to said gear-motor and adapted for sliding engagement within said housing along the axis of said printing member; said gear-motor including an output shaft coupled to said printing member through said elliptical wave-generator and said flexible spline; said first worm gear having internal screw threads in operative engagement with corresponding external threads on said movable support; and a handwheel coupled to said second worm gear for rotating said first worm gear through said second gear whereby said first worm gear axially shifts said movable support to thereby shift said printing member through said output shaft coupled to said printing member.
 6. The apparatus of claim 5 wherein said axial indicator means includes a pointer secured to said movable support and a graduated scale secured to said stationary housing adjacent said pointer whereby axial movement of said support moves said pointer along scale for Indicating the axial shift of said printing member.
 7. Apparatus for changing the angular phase of first and second printing rollers with respect to driving means therefor and with respect to each other and for changing the axial position of said rollers comprising, in combination: a first spur gear mounted on one end of said first printing roller rotatable relative thereby by said driving means; a second spur gear mounted on one end of said second printing roller rotatable relative thereby by said first spur gear; substantially identical phase shifting apparatus coaxially coupled to each of said spur gears, each shifting apparatus having an input rotatably driven by its associated spur gear and an output coupled to its respective printing roller, each shifting apparatus having a coaxial wave-generator radially aligned between said input and said output for changing the angular phase of said output with respect to said input whereby the angular phase of said first printing roller is changed with respect to said driving means upon rotation of its associated wave-generator and the angular phase of said second printing roller is changed with respect to said first printing roller upon rotation of its associated wave-generator; each of said phase shifting apparatus including: a. a rigid circular spline secured for rotation with said driving member and having internal spline teeth thereon; b. a flexible circular spline of smaller diameter than said rigid spline supported within said rigid spline and having external spline teeth thereon; c. an elliptical wave-generator supported within said flexible spline and adapted to deflect said flexible spline to a corresponding elliptical shape for urging said external teeth into meshing engagement with said internal teeth substantially opposite the foci of said elliptical wave-generator; a gear-motor for each of said phase shifting apparatus having a primary output coaxially coupled to its respective printing member through said wave-generator and said flexible spline for selectively rotating said wave-generator in either a clockwise or counterclockwise direction during rotation or nonrotation of said driving member thereby changing the radially angular position of meshing engagement between said internal and external teeth; axial end-adjustment means for each of said printing rollers including: first and second worm gears fixed in rotatable operative engagement in a stationary housing; a movable support secured to said gear-motor and adapted for sliding engagement within said housing along the axis of said printing member; said gear-motor including an output shaft coupled to said printing member through said elliptical wave-generator and said flexible spline; said first worm gear having internal screw threads in operative engagement with corresponding external threads on said movable support; each of said second worm gears having a handwheel coupled thereto for rotating said worm gears whereby said first worm gear axially shifts its associated movable support to thereby shift its associated printing roller; indicator means coaxially coupled to each of said gear-motors including a third worm coupled with a secondary output of said gear-motor for driving a fourth worm wheel in operative rotatable engagement therewith and a graduated dial coupled to said fourth worm wheel for indicating the direction and distance of the phase shift of the associated printing roller; and axial indicator ma means associated with each of said gear-motors including a pointer secured to said movable support and a graduated scale secured to said stationary housing adjacent said pointer whereby axial movement of said support by said handwheel moves said pointer along said scale for indicating the axial shift of each of said printing rollers. 